To determine the speed and distance of objects in road traffic, it is conventional to use pulsed radar systems (PCT International Patent Publication No. WO 99/42856). It is known from German Patent Application No. DE 44 12 77 that overlapping antenna lobes may be produced for an automotive distance warning radar; the radar lobes may also be directed. Either an exciter system is used as the transceiver antenna there or separate transmitting and receiving antennas are provided.
PCT International Patent Publication No. WO 02/15334 describes a multiple beam antenna array having a beam forming network and a beam combining network. Measures are implemented there so that the transmitting and receiving lobes point in exactly the same direction.